1,720,974 research outputs found
The Synergistic Effect Of Tannins And Iodide Ions On The Corrosion Inhibition Of Mild Steel In Corrosive Media
Get PDFThe inhibition effect of mangrove tannin (MgT), mimosa tannin (MmT) and chestnut tannin (CnT) on the corrosion behaviour of mild steel in 0.5 M HCl, 0.25 M H2SO4 and 3.5 % NaCl solutions was studied using weight loss, potentiodynamic polarisation and electrochemical impedance spectroscopy (EIS) techniques. The results from all techniques studied showed that MgT gave satisfactory inhibition efficiencies on mild steel. The performance of MgT was further enhanced when iodide ions were added into the corrosive media containing this inhibitor, indicating the occurrence of synergism between these two compounds. In the weight loss analyses, the inhibition efficiencies for all three tannins have been increased from 38-85 % to 82-97 % when iodide ions were introduced into the corrosive media containing these inhibitors. The inhibition efficiencies for all three tannins were enhanced from 47-89 % to 83-94 % when combined with iodide ions in the potentiodynamic polarisation measurements. In the EIS measurements, the inhibition efficiencies for all three tannins were further increased from 69-84 % to 80-92 % when these tannins were synergised by the iodide ions. The inhibition efficiencies obtained from the weight loss and electrochemical measurements were in good agreement. Potentiodynamic polarisation studies clearly revealed that MgT behaved as mixed-type inhibitor with predominant anodic effectiveness. The Nyquist plots obtained from the EIS analyses showed that the inhibition process was mainly controlled by a charge transfer process
Adsorptive natural zeolite ceramic membrane for ammonia removal in wastewater
Get PDFAdsorption process is known as a promising way for ammonia elimination. Owing to the fact that natural zeolite (clinoptilolite) has a superior property of ion-exchange and adsorption, the removal of ammonia by natural zeolite is a strategic approach. However, the conventional approach of powder suspension adsorption might be ineffective due to some drawbacks such as the requirement of secondary treatment after the adsorption has taken place as well as the loss of adsorbent during the filtration and regeneration processes. The use of membrane technology can overcome this difficulty by combining adsorption and filtration in a single step. Therefore, this study aims to develop hybrid adsorptive natural zeolite based hollow fibre ceramic membrane (HFCM) via phase-inversion and sintering techniques. The fabrication parameters namely ceramic loading, air-gap distance, bore fluid flowrate, sintering temperature and natural zeolite clinoptilolite sieved particle size were studied. The properties of the prepared ceramic membranes were characterized in terms of morphologies, bending strengths, water permeabilities and porosities. The performance of the membrane for ammonia removal was studied using the synthetic ammonia wastewater in a crossflow system. The factors affected the adsorption performance specifically the membrane sintering temperature, natural zeolite clinoptilolite particle size, pH of the ammonia feed solution, ammonia initial feed concentration and HFCM dosage were examined in this study. The regeneration process of the used adsorptive ceramic membrane was investigated for the reusability study. Clinoptilolite has shown great potential as a good adsorptive membrane that targeting the uptake of contaminant cations in water treatment process. The results have also shown that the fabricated HFCM was successfully produced when spun at 45 wt.% ceramic loading, 5 cm of air-gap distance and 15 mL/min of bore fluid flowrate, sintered at 1050 °C and best fabricated using 36 µm sieved particle size. The produced HFCM exhibited desired morphologies with good bending strength and water permeation. The adsorptive HFCM demonstrated ammonia rejection of more than 90%. The optimization study has shown that the optimum condition of the adsorptive HFCM was found to be at pH 7.04, 75.00 mg/L and 0.35 g of feed pH, feed concentration and HFCM dosage, respectively. The optimum water permeability and ammonia removal were found to be of 281.9 L/m2?h and 94.14 %, respectively. The confirmatory test has revealed that the optimum performance was acceptable with average error of 1.64% and 1.85% for water permeability and ammonia removal, respectively
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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